UCLA

Zebrafish (Danio rerio) holds a promise as a model vertebrate system for neurobiological investigations of learning and memory. Here, we sought to demonstrate two forms of nonassociative learning: first, short-term sensitization of tail movements and second, long-term sensitization of thigmotaxis, induced by application of allyl isothiocyanate, a chemical irritant, in both restrained and free-swimming larval zebrafish. We found that allyl isothiocyanate increased both tail movements and tail movements’ duration for several minutes after the chemical irritant was removed from the bath. Moreover, pharmacological manipulations were observed to alter the behavior. Experimental manipulations included exposure to methiothepin, an antagonist of serotonin (5-HT) receptors. Methiothepin application was observed to block MO-induced sensitization of thigmotaxis in larval zebrafish. Our results demonstrate that a noxious stimulus, allyl isothiocyanate, can reliably induced tail movements and thigmotaxis sensitization in both restrained and free-swimming larval zebrafish, and thus facilitate future investigations of in vivo neural circuits.